So-called raw-edged endless substantially trapezoidal power transmission belts are often used in torque sensing drives, in applications where each belt is maintained under spring tension, or the like; and, it has been found that a high belt to sheave coefficient of friction results in a comparatively high total belt tension and a reduced belt to sheave coefficient of friction results in a reduced total belt tension. Accordingly, it is desirable in drives and applications of the character mentioned to provide a raw-edged belt, i.e., one having raw-edged non-parallel sides, which is capable of operating under reduced belt tension due to its reduced coefficient of friction non-parallel sides.